| 摘要 |
PURPOSE:To prevent separation of coating and corrosion of a spring strand, by preheating a spring main unit and then blowing it from a spray gun with a flame and welding a thermoplastic resin pulverulent body of melting point not higher than 250 deg.C to at least a part of the spring strands mutually contacting to each other. CONSTITUTION:In a spring strand 2 of a coil spring main unit 1, coated parts 3 are provided, while covering at least a part of a strand facing the neighboring spring strand 2. This coated part 3 is formed by preheating a main unit 1 to about 100- 250 deg.C of surface temperature of the spring strand 2 and then injecting from a spray gun with a flame a thermoplastic resin pulverulent body, for instance, denatured ethylic acid vinyl copolymer of melting point not higher than 250 deg.C and welding to the surface. The coated part 3, being welded to the spring strand 2, prevents water from intruding between the coating and strand, further firm adhesion can prevent separation of the coating and corrosion of the spring winding 2. |
